Metal-plated honeycomb-shaped boron carbonitride nanomaterials and their applications

Abstract

The present invention discloses 3D rigid mesoporous honeycomb-like boron carbonitride (HBCN) nanomaterials as hosts for plating / depositing metals, which are used as metallic anodes in alkali metal ion batteries.

Description

[Technical Field]

[0001] The present invention relates to 3D rigid mesoporous honeycomb-like boron carbonitride (HBCN) nanomaterials as hosts for metal plating / deposition, which are used as metal anodes in alkali metal ion batteries. [Background technology]

[0002] State-of-the-art commercially available lithium-ion batteries (LIBs) based on graphite and lithium transition metal oxides (LTMOs) have a capacity of ~250 Wh / kg -1 Although they offer energy densities of 1000 mAhcm, which is extremely low relative to the energy density requirements for current mobility applications (Richard Van Noorden, Nature, 2014, 507, 26, 2. Eric C. Evarts, Nature, 2015, 526, 593). Ideal anode and cathode combinations in Li-ion configurations do not even come close to those projected for light electric vehicles, and practical Li-ion batteries offer capacities of 6 mAhcm. -2 (Goodenough JB, Park KS, Journal of the American Chemical Society, 2013, 135(4),1167-76). However, by replacing graphite with lithium metal, i.e., by improving the Li metal composition, new hope is emerging, as it is expected to achieve high energy densities that are close to current demands. For example, currently commercially available graphite-based LIBs have capacities of 100-265 Wh / kg. -1 While Li and LTMO batteries can have energy densities in the range of about 440 Wh kg -1 Furthermore, using Li metal as the anode in Li-S and Li-O configurations can deliver energy densities of 600-650 Wh / kg. -1 and 900-950Whkg -1Energy densities of 1000kJ / cm2 can be achieved, respectively (Bruce PG, Freunberger SA, Hardwick LJ, Tarascon JM, Nature Materials, 2012,11, 19-29.9).

[0003] However, the high reactivity of lithium poses formidable challenges: dendrite growth and subsequent cell short-circuiting, which represents a serious safety issue. Uncontrolled dendrite growth in the case of Li, which is also contributed by non-uniform electrodeposition and large capacity variations, directly affects the solid electrolyte interface (SEI) that forms on the electrode material. Therefore, the main initiators of dendrite formation, in addition to the high reactivity of Li, are: 1) non-uniform Li flux due to cation deficiency, 2) non-uniform nucleation due to inhomogeneous Li conductivity, and 3) cracking of the SEI due to large capacity variations and resulting stresses. Recently, several strategies have been demonstrated to understand and counter these initiators, with the aim of suppressing dendrite growth for stable Li anode performance. Apart from some electrolyte engineering, most of the literature has been focused on surface and bulk modifications of potential Li hosts. Furthermore, pristine carbon networks provide conductive pathways that guide lithium plating. However, modifications to the carbon matrix, such as the incorporation of lithophilic hosts into the carbon, improve the efficiency of lithium deposition by suppressing dendrites and regulating lithium deposition (Xiang Chen et al., "Lithiophilicity chemistry of heteroatom-doped carbon to guide uniform lithium nucleation in lithium metal anodes," Sci. Adv. 2019;5: eaau7728, 15 February 2019). Heteroatoms such as nitrogen and boron, due to their electron-rich nature, help provide adequate contact with lithium and aid in uniform lithium deposition on the electrode surface. Stable coulombic efficiency and cycle life are achieved through uniform lithium deposition due to the induced plating of dopants present in the carbon matrix.

[0004] Taking all this into consideration, there is provided herein the first nitrogen and boron doped mesoporous 3D honeycomb boron carbonitride (HBCN) nanomaterials for application as host materials for depositing lithium into the pores and as lithium metal anodes in Li-ion batteries, which meets the need in the art. Summary of the Invention [Problem to be solved by the invention]

[0005] The primary object of the present invention is to provide a metal-plated boron carbonitride (BCN) material characterized in that the BCN material has a honeycomb morphology.

[0006] Another object is to provide an in-situ process for the fabrication of mesoporous 3D honeycomb-like boron carbonitride (HBCN) nanomaterials.

[0007] Another object of the present invention is to provide a battery containing 3D honeycomb structured boron carbonitride as a metallic anode. [Means for solving the problem]

[0008] Thus, the present invention provides 3D rigid mesoporous honeycomb boron carbonitride (HBCN) nanomaterials with porosity in the range of 300-500 nm and mesoporosity in the range of 2-10 nm as a host for plating / depositing metals.

[0009] The metal deposited is selected from lithium, sodium, magnesium or aluminum.

[0010] In one embodiment, the 3D rigid mesoporous nanomaterial of boron carbonitride (HBCN) has a thickness of 400-800 m 2 g -1 The surface area is in the range of

[0011] In another aspect, the present invention provides a method for producing a pharmaceutical composition comprising: a) adding tetraethyl orthosilicate (TEOS) to a mixture of water, alcohol, and ammonium solution, followed by stirring to provide a reaction mixture; b) adding the TEOS solution to the mixture of step (a) and continuing to stir to provide silica nanoparticles; c) separating and washing the silica nanoparticles of step (b) by centrifugation, followed by drying to obtain dried colloidal silica nanoparticles SiO2NPs; d) infiltrating the mixture of boric acid, carbon precursor and cyanamide solution with colloidal SiO2 NPs and drying the resulting material, followed by pyrolysis in inert gas to give silica NPs / BCN; e) treating the silica NPs / BCN from step (d) with HF solution to completely dissolve / remove the SiO2 NPs from the product, followed by washing and drying to obtain 3D honeycomb boron carbonitride (HBCN); The present invention provides a cost-effective process for the production of 3D honeycomb boron carbonitride, including:

[0012] Metal-plated / deposited 3D rigid mesoporous honeycomb-like boron carbonitride (HBCN) nanomaterials with porosity in the range of 300–500 nm and mesoporosity in the range of 2–10 nm are used as anode materials for alkali metal-ion batteries.

[0013] In another aspect, the present invention provides a 3D honeycomb boron carbonitride having a porosity in the range of 300-500 nm and a mesoporosity in the range of 2-10 nm, comprising an alkali metal ion plated / deposited on the honeycomb boron carbonitride mesoporous structure. An anode for a potash metal battery is provided.

[0014] The alkali metal ion battery may include a lithium ion battery, a lithium sulfur battery, a sodium ion battery, a sodium sulfur battery, and the deposited metal is selected from lithium, sodium, magnesium or aluminum, preferably lithium and sodium.

[0015] In one aspect, the present invention provides a lithium-ion battery with improved stability and long life cycle comprising a 3D honeycomb boron carbonitride metal anode having porosity in the range of 300-500 nm and mesoporosity in the range of 2-10 nm, plated / deposited with lithium.

[0016] In another aspect, the present invention provides a method for producing a pharmaceutical composition comprising: (i) a cathode; (ii) an anode comprising a 3D honeycomb boron carbonitride plated / deposited with alkali metal ions, the anode having a porosity in the range of 300-500 nm and a mesoporosity in the range of 2-10 nm; (iii) an electrolyte disposed between the cathode and the anode, the electrolyte comprising an alkali salt and a solvent; (iv) a separator; and The present invention provides an alkali metal plated full cell comprising: [Brief explanation of the drawings]

[0017] [Figure 1] (a) XRD patterns and (b) Raman spectra of carbon sheet, honeycomb carbon, BCN sheet, and HBCN. [Figure 2] SEM images of (a) carbon sheet, (b) honeycomb carbon, (c) BCN sheet, and (d) HBCN. [Figure 3] (a) XPS survey spectrum of BCN, (b) B1s, (c) C1s, and (d) N1s high-resolution XPS spectra of BCN. [Figure 4] High-resolution XPS spectra of (a) C1s, (b) B1s, and (c) N1s of HBCN. [Figure 5] N2 adsorption isotherms (a and c) and pore size distributions (b and d) of carbon sheet and HBCN samples, respectively. [Figure 6](a) SEM image of silica nanoparticles, (b) SEM image of silica NPs / BCN after heating at 900 °C, (c-e) SEM images of 3D HBCN, (f-g) TEM images, (h) SAED pattern, (i) High-Angle Scattering Dark-Field Scanning Transmission Electron Microscopy (HAADF-STEM) image, (j) TEM elemental mapping of boron, (k) elemental mapping of carbon, (l) elemental mapping of nitrogen. [Figure 7] Plating-stripping performance of HBCN at 4 mA cm-2 and 10 mAh cm-2. (a) Voltage-time profile, (b) Coulombic efficiency of plating-stripping, (c) voltage profile at selected cycles of plating-stripping, (d) evolution of hysteresis with plating-stripping cycles. [Figure 8] (a) Voltage-time profile and (b) Coulombic efficiency of rate performance of HBCN at 2 mAh cm-2 areal capacity depositions, (c) full-cell performance of plated HBCN and LFP at 50 mA g-2 current density, and (d) full-cell charge-discharge profile. [Figure 9] Li plating / stripping performance at 4 mA cm-2 current and 10 mAh cm-2 capacity. (a, c, and e) Voltage vs. time plots, and (b, d, and f) Coulombic efficiency vs. cycle plots for carbon sheet, HC, and BCN, respectively. [Figure 10] Li plating-stripping performance of HBCN at 8 mA cm-2 current density and 10 mAh cm-2 capacitance value. (a) Voltage vs. time plot, (b) plating / stripping, coulombic efficiency and cycling stability, (c) voltage profile at selected cycles, and (d) evolution of voltage hysteresis with cycling operation. [Figure 11] Electrochemical Na de-plating of HBCN at 8 mAhcm-2 current density and various Na intake capacity values. (a and c) V vs time plots at 2 mAhcm-2 and 1 mAhcm-2 capacity values, respectively. (b and d) Coulombic efficiency plots at 2 mAhcm-2 and 1 mAhcm-2 capacity values, respectively. DETAILED DESCRIPTION OF THE INVENTION

[0018] In order that its various aspects may be more fully understood and appreciated, the invention will now be described in detail in connection with certain preferred and optional embodiments.

[0019] In one embodiment, the present invention relates to 3D rigid mesoporous honeycomb boron carbonitride (HBCN) nanomaterials with porosity in the range of 300-500 nm and mesoporosity in the range of 2-10 nm as a host for metal plating / deposition.

[0020] The metal deposited is selected from lithium, sodium, magnesium or aluminum.

[0021] In one embodiment, the 3D rigid mesoporous nanomaterial of boron carbonitride (HBCN) has a thickness of 400-800 m 2 g -1 The surface area is in the range of

[0022] In another embodiment, the present invention provides a) adding tetraethyl orthosilicate (TEOS) to a mixture of water and alcohol, preferably isopropyl alcohol, and ammonium solution, followed by stirring at a temperature in the range of 25°C to 30°C for a time in the range of 1 to 2 hours to give a reaction mixture; b) adding TEOS solution to the mixture of step (a) and continuing to stir at a temperature in the range of 25°C to 40°C for 2 to 4 hours to obtain silica nanoparticles; c) separating the silica nanoparticles of step (b) by centrifugation, washing with water and alcohol, and then drying to obtain dried colloidal silica nanoparticles SiO2NPs; d) infiltrating the mixture of boric acid, carbon precursor and cyanamide solution with colloidal SiO2 NPs and drying the resulting material at a temperature in the range of 50°C-100°C, followed by pyrolysis in an inert gas atmosphere at a temperature in the range of 700°C-1000°C to give silica / BCN; e) treating the silica / BCN from step (d) with HF solution for 10-14 hours to completely dissolve / remove SiO2 NPs from the product, followed by washing with water and drying to obtain 3D honeycomb boron carbonitride (HBCN); A cost-effective process for the production of 3D honeycomb boron carbonitride is disclosed, including:

[0023] The carbon precursor is selected from glucose, sucrose, cellulose or fructose.

[0024] The process for producing honeycomb boron carbonitride is as shown in Scheme 1 below:

[0025] [ka]

[0026] In one embodiment, 3D honeycomb boron carbonitride with porosity in the range of 300-500 nm and mesoporosity in the range of 2-10 nm with plated / deposited ions is used as a metal anode in an alkali metal battery.

[0027] In yet another embodiment, the present invention discloses an anode for an alkali metal battery comprising 3D honeycomb boron carbonitride having porosity in the range of 300-500 nm and mesoporosity in the range of 2-10 nm, with alkali metal ions plated / deposited on the honeycomb boron carbonitride mesoporous structure.

[0028] Alkali metal ions are deposited onto the 3D honeycomb boron carbonitride structures via an electrochemical route.

[0029] The metal is selected from lithium, sodium, magnesium, or aluminum. The metal is preferably lithium. The alkali metal ion battery may include a lithium ion battery, a lithium sulfur battery, a sodium ion battery, or a sodium sulfur battery.

[0030] In one embodiment, the 3D HBCN of the present invention itself has an inherently conductive and interconnected structure, and heteroatoms such as B and N dopants provide guided paths for smooth Li / Na plating onto the surface.

[0031] In one embodiment, the 3D HBCN is 8 mAcm -2 High current and 10mAhcm -2 It exhibits stable dendrite-free Li plating / peeling performance for over 2400 cycles with large capacity Li uptake.

[0032] In a preferred embodiment, the present invention relates to a lithium-ion battery comprising 3D honeycomb boron carbonitride having porosity in the range of 300-500 nm and mesoporosity in the range of 2-10 nm plated / deposited with lithium as an anode material.

[0033] In another embodiment, the process for the manufacture of a prelithiated electrode for use as an anode in a lithium ion battery after lithium deposition comprises: (i) Mixing 3D HBCN with porosity in the range of 300-500 nm and mesoporosity in the range of 2-10 nm, a conductive additive (Super P), and a PVDF binder in a ratio of 80:10:10 in NMP solvent; (ii) coating the as-prepared slurry in step (i) onto a copper foil used as a current collector, followed by drying overnight; and (iii) cutting a circular electrode with a diameter of 14 mm; Includes.

[0034] In one embodiment, a lithium metal battery (half cell) of the invention having 3D HBCN as the Li metal anode achieved a current density of 8 mAh cm for over 2400 cycles in 1 M LiTFSI and 0.3 M LiNO in dioxolane (DOL) / dimethoxyethane (DME) electrolyte. -2 High current density of 10 mAhcm -2It exhibits a coulombic efficiency (CE) of 99.98% when subjected to a large Li uptake capacity value of 1.0.

[0035] In yet another embodiment, the present invention provides a) with standard LiFePO4 (LFP) as cathode; b) 3D honeycomb boron carbonitride with porosity in the range of 300-500 nm and mesoporosity in the range of 2-10 nm, plated / deposited with lithium as an anode; c) an electrolyte containing 1M LiPF6 in 1:1:1 (v / v / v) EC / DMC / EMC (i.e., ethylene carbonate / dimethyl carbonate / ethyl methyl carbonate) with 5% fluoroethylene carbonate (FEC); d) Quartz fiber paper or Celgard as a separator separating the negative and positive electrodes; A lithium-plated full cell is disclosed, comprising:

[0036] With reference to the figures, the detailed description of the present invention is as follows: Thus, the PXRD patterns of the carbon sheets, honeycomb carbon, BCN sheets, HBCN, shown in Figure 1(a) show two broad peaks for the (002) and (100) major planes, indicating the nature of graphitic carbon.

[0037] Raman analysis was carried out on carbon sheet, honeycomb carbon, BCN sheet, and HBCN as shown in Figure 1(b). The Raman spectra of all the samples show the presence of D and G bands. The G band is due to sp 2 The D band, which corresponds to the in-plane carbon atom stretching vibration caused by carbon, is also known as the defect band. 3 Due to the presence of carbon, carbon sheet, honeycomb carbon, BCN sheet, and HBCN show a Raman shift of the D band of 1325 cm -1 A similar Raman shift phenomenon was observed at the G band position, with a peak at 1588 cm -1 Shows peaks before and after.

[0038] Figure 2 shows SEM images of the carbon sheet, honeycomb carbon, BCN sheet, and HBCN samples, which clearly show the sheet-like morphology and honeycomb structure in both the carbon and BCN samples.

[0039] XRS analysis indicates the presence of B, C, N, and O in BCN (Figure 3a). Therefore, elemental analysis was performed on these elements. Figure 3b shows the B1s spectrum, which can be deconvoluted into two peaks at binding energies of 190.3 and 191.9 eV, associated with BC and BN bonds, respectively. Figure 3c shows the C1s spectrum, deconvoluted into four peaks at 283.4, 284.3, 285.7, and 288.5 eV, assigned to CB, CC, CN, and CO, respectively. The N1s spectrum, shown in Figure 3d, is deconvoluted into three peaks at 397.9, 399.41, and 401.12 eV, corresponding to NB, NC (pyridinic and graphitic). All peaks thus confirm the formation of bonds between CB, CN, CO, and BN.

[0040] The high-resolution X-ray photoelectron spectroscopy (XPS) spectrum of the C1s of H-BCN (Figure 4a) can be deconvoluted to 283.8, 284.3, 285.8, and 288.2 eV, which are attributed to C-B, C-C, C-N, and C-O bonds, respectively. The high-resolution spectrum of the B1s of H-BCN (Figure 4b) shows two deconvoluted peaks at 189.8 and 191.6 eV, which correspond to B-C and B-N bonds, respectively. Similarly, the high-resolution spectrum of the N1s of H-BCN (Figure 4c) shows three deconvoluted peaks at 397.3, 399.4, and 401.7 eV, which are attributed to N-B, N-C pyridinic, and N-C graphitic bonds, respectively. XPS studies have revealed that e - The missing B creates a bond between C and N, e - The phosphate-rich N donates its lone pair to act as a Lewis base, forming the Lewis acid Li through a powerful acid-base reaction. + This study provides insight into the B and N doping of honeycomb-shaped carbon (HBCN) for metal anode applications, which strongly adsorbs ions.

[0041] The specific surface areas of the honeycomb BCN, BCN sheet, honeycomb carbon, and carbon sheet are 597, 358, 276, and 10 m, respectively. 2 g -1 The N adsorption / desorption isotherms and pore size distributions of the carbon sheet and HBCN are shown in Figure 5. The carbon sheet exhibited a 10 m 2 g -1 HBCN exhibited a surface area of ​​597 m (Fig. 5a) and a pore size distribution of 10–30 nm (Fig. 5b). 2 g -1 exhibited the largest surface area of ​​all prepared carbon samples (Fig. 5c) and pore size in the range of less than 20 nm (Fig. 5d).

[0042] [Table 1]

[0043] In an embodiment of the process of the present invention, spherical silica NPs with uniform size (around 500 nm) were produced by utilizing the well-known Stober method. Furthermore, silica NPs with sizes in the range of 50–500 nm can be synthesized using the Stober method. In the present invention, silica NPs with sizes around 300–500 nm were synthesized. The formation of uniform spherical silica NPs was confirmed by SEM images (Figure 6a). A mixture of glucose (or cellulose, sucrose, or fructose can also be used as a carbon precursor), boric acid, and cyanamide was then infiltrated into the silica NPs and then pyrolyzed at 900 °C, resulting in the formation of a uniform BCN layer on the silica NPs, as confirmed by SEM images (Figure 6b). In the process of the present invention, random formation of any agglomerates from the precursor was not observed. Figures 6(c–e) show SEM images of HBCN obtained from the silica NPs / BCN composite after etching the silica NPs with HF solution. The diameter of the spherical pores formed on the BCN layer after etching of the silica NPs is roughly similar to that of the silica NPs, creating a 3D structure. The 3D structure is uniformly generated throughout the BCN, tending to introduce a honeycomb sponge-like structure into the BCN material. Furthermore, the porosity and structural morphology of the 3D HBCN were examined by TEM imaging. The TEM images are shown in Figures 6(f) and 6(g), displaying the honeycomb-like porous 3D morphology of the HBCN. Figure 6(h) shows the selected-area electron diffraction (SAED) pattern of the HBCN. The diffuse diffraction rings indicate the amorphous / polycrystalline nature. The diffraction rings correspond to the (002) and (100) planes of carbon. Elemental mapping of the 3D HBCN was performed by TEM, and the corresponding images are shown in Figures 6(i)–6(l). The elemental mapping images indicate the even distribution of B, C, and N within the 3D HBCN material.

[0044] The phase purity and crystalline structure of the 3D HBCN network were characterized by powder XRD. The diffraction pattern observed for the carbon material is shown in Figure 1(a). The broad peaks of the major crystallographic planes (002) and (001) of graphite indicate a turbostratic structure. From the PXRD pattern of HBCN, the d value of the (002) plane was found to be 3.5 nm. To obtain deeper structural information, Raman spectra were measured at an excitation wavelength of 632.8 nm. The Raman plot is shown in Figure 1(b). Two strong peaks at 1325 cm correspond to the D and G bands of graphite, respectively. -1 and 1594 cm -1 This prominent defect band may be due to two reasons: the high porosity of carbon in the 3D HBCN network with oxygen functional groups and the presence of nitrogen and boron doping. In addition, a distinct defect band at 2689 cm, which corresponds to the 2D band of graphite, was observed. -1 Weak broadening of the HBCN structure was observed, suggesting stronger 3D linkages within the carbon network. Nitrogen adsorption / desorption studies were performed to understand the porosity of the HBCN material, and the corresponding plots are shown in Figures 5(c) and (d). The isotherm of HBCN shown in Figure 5(c) exhibits a type IV isotherm, indicating monolayer N adsorption at lower relative pressures, while the hysteresis at higher relative pressures is 597 m. 2 g -1 The pore size distribution obtained from the nitrogen desorption curve shows the presence of mesopores in HBCN with a total surface area of ​​0.84 cm. 3 g -1 The total pore volume of 1000 Å was 1000 Å. The high surface area and pore volume enhanced the Li plating-stripping performance as a short diffusion path for Li ions provided excellent accessibility at the active sites, indicating good electrode-electrolyte contact. Such a high surface area suggests a low current density, i.e., a uniform flux for lithium deposition.

[0045] This interconnected nanoscale carbon provided a large, basic, lithophilic carbon surface area for Li electrodeposition during charging. The porous structure ensured easy diffusion and mitigated non-uniform Li flux, which could cause local space charge generation and, in turn, lead to dendrites. In addition, heteroatom doping could functionalize the surface for better lithophilicity.

[0046] The lithium deposition / dissolution, i.e., plating / stripping behavior, of the as-prepared HBCN material was tested in a half-cell assembly. Coulombic efficiency is the most important parameter to consider the sustainability of any lithium metal anode. Coulombic efficiency is the ratio of the total amount of lithium stripped from the working electrode to the total amount of lithium deposited on the working electrode. During plating, Li + Ions are deposited on the working electrode from the Li disk counter electrode and upon peeling, Li + The ions become detached and return to the Li disk counter electrode. In general, coulombic efficiency depends on both current density and areal capacitance. For this reason, it is important to test any lithium metal anode at different current densities and areal capacitance values. -2 Current density and 10mAhcm -2 The plating-peel behavior of HBCN coated on copper foil at an areal capacitance value of 0.01 is shown in Figure 7. From Figure 7(a), a stable and uniform voltage profile of HBCN was identified from only the first cycle. Uniform plating-peel behavior of HBCN was observed for over 400 cycles with a Coulombic efficiency of 99.94% (Figure 7(b)). This enhanced performance is attributed to the uniform flux distribution on the high-surface-area HBCN material, which provides a nanoscale interconnected carbon network. Furthermore, nitrogen and boron doping in the carbon matrix plays a crucial role: they regulate lithium nucleation to provide guided lithium plating, thereby suppressing dendrite growth. This contributes to stable long-term cycling performance. Due to its high apparent surface area, HBCN can undergo very low current densities, thereby extending the dendrite formation time and maintaining a stable, stress-free SEI over the cycling period.

[0047] Figure 7(c) shows the Li electrodeposition overpotential from the voltage difference between the plating potential plateau and the stripping potential plateau. The net overpotential is (i) Li through the SEI. + Ion diffusion limited and (ii) This can arise from the charge transfer overpotential for Li deposition on HBCN-coated copper. The overpotential for Li deposition on HBCN-coated copper is around 145.2 mV in the first cycle. From Figure 7c, it can be seen that in the first plating, the potential is + The voltage drops to -4000mV relative to the -2 Current density and 10mAhcm -2 This is the largest potential drop across all experiments performed at capacitance values, which is the largest potential drop across the SEI due to transport through the SEI at such high current rates and capacitance values. + However, the overpotential drops dramatically and stabilizes after only the second cycle. This drop in overpotential during cycling is due to the transfer of new Li to the previously deposited ions. + As shown in Figure 7(d), overpotentials of 26.6, 26.2, 25.5, 25.3, and 25.4 mV were observed at the second, third, fifth, tenth, and twentieth cycles, respectively, and stabilized at a value of 24.6 mV after 100 cycles. The overpotential became stable from just the second cycle, which is attributed to the robust SEI layer formed on the mesoporous structure, enabling efficient Li transport through the mesoporous structure. + This Coulombic efficiency (CE) value was maintained even after 400 plating / stripping cycles amounting to 2000 hours.

[0048] The speed performance of HBCN is 2mAhcm -2 The measurements were carried out at a constant areal capacity of 1, 2, 4, 6, 4, 2, and 1 mAcm (Figures 8(a) and (b)). -2An areal current density of 1000 kJ / cm was applied to the HBCN. Stable Coulombic efficiency performance was achieved at different current values, with negligible potential drops at different current rates. This was attributed to the mesoporous structure with two heteroatom doping in the carbon matrix, which regulated the surface lithium flux even at higher current rates.

[0049] In another embodiment, the feasibility of lithium-plating HBCN in a full cell was tested in a full cell configuration with LiFePO4 (LFP) as the cathode and pre-lithiated HBCN as the anode. -1 The charge-discharge cycling performance of the Li-HBCN||LFP full cell at different current densities is shown in Figure 8(c) and 8(d), respectively. This full cell had a capacity of 110 mAhg after 50 cycles. -1 A capacitance value of 100% indicates 100% coulombic efficiency.

[0050] 4mAcm showed very poor performance -2 Current and 10mAhcm -2 The Li plating / stripping performance of the carbon sample in terms of capacity is shown in the voltage vs. time plot and the Coulombic efficiency vs. cycle plot in Figures 9(a) and (b), respectively. This is due to the very low surface area of ​​the material, which provides fewer Li nucleation sites; the planar surface causes inhomogeneous Li deposition, which further develops into dendritic growth. Furthermore, the absence of heterodoping in C leads to poor Li fixation, resulting in poor performance. Within 20 plating / stripping cycles, the Coulombic efficiency drops rapidly.

[0051] Similar to the flat carbon sheet, the honeycomb carbon (HC) sample also exhibited a 4 mAcm -2 Current and 10mAhcm -2The capacity shows poor Li plating / stripping performance (Figure 9(c) and 9(d)). The Coulombic efficiency drops within only 40 cycles. Compared to a planar carbon sheet, the larger surface area of ​​the HC contributes to larger Li nucleation sites. However, the lithiphobic nature of carbon and the lack of lithophilic functional groups with strong binding affinity to lithium atoms result in poor performance. This, in turn, leads to inhomogeneous Li flux distribution and dendrite growth.

[0052] 4mAcm -2 Current density and 10mAhcm -2 The Li plating / peeling performance of the BCN material at the capacitance value is shown in Figure 9(e) and (f), respectively. Similar to the planar carbon and honeycomb carbon materials, poor Li plating / peeling performance was observed for the BCN material. In the case of BCN, although lithophilic dopants B and N are present, the sheet-like morphology provides inhomogeneous Li flux distribution within the material, resulting in poor performance.

[0053] The battery performance of the planar carbon sheet, honeycomb carbon, BCN sheet, and honeycomb BCN indicates that both the honeycomb structure and BN doping into carbon are optimal requirements for uniform Li plating / peeling application.

[0054] Figure 10 shows the -2 High current density and 10mAhcm -2 This figure shows the experimental results of the plating / stripping performance of HBCN with a heavy Li deposition on the surface of the electrode. The first inset graph in Fig. 10(a) easily shows that the voltage vs. time plot is not uniform in nature for the first few cycles. This is because the plating occurs below the SEI layer, and Li is transported through the electrolyte and across the solid-electrolyte interface. +However, the performance stabilizes within 10 cycles. The coulombic efficiency obtained with such a high current rate and heavy Li deposition capability is excellent, reaching 99.98% after 2437 cycles (Fig. 10(b)). This enhanced performance is attributed to the uniform flux distribution in the high-surface-area HBCN material with its nanoscale interconnected carbon network. Furthermore, nitrogen and boron doping in the carbon matrix plays a crucial role, as nitrogen and boron modulate lithium nucleation and provide guided lithium plating, thereby suppressing dendrite growth. This contributes to the stable long-term cycling performance.

[0055] Figure 10(c) also gives an idea of ​​the Li deposition kinetics in terms of the Li electrodeposition overpotential calculated from the voltage difference between the plating potential plateau and the stripping potential plateau. The net overpotential is (i) the Li deposition through the SEI. + This can arise from (i) ion diffusion limitation and (ii) charge transfer overpotential for plating. The nucleation overpotential for Li deposition on HBCN was 461.3 mV in the first cycle, which was 8 mA cm -2 and 10mAhcm -2 The best current experiment with parameters, Li + This can be attributed to the kinetic hindrance imposed on the Li-ion. In the second cycle, the nucleation overpotential dropped drastically to 87.4 mV and then stabilized. Furthermore, the voltage hysteresis in the plating / stripping process, referred to as the overpotential, is the difference between the plateau potential and the plateau potential. This gives an idea of ​​the mass transport behavior of Li during the plating / stripping cycles. As shown in Figure 10(d), overpotentials of 197.3, 139.8, 128.65, 16.7, 19.1, 26.5, 26.7, and 22.7 mV were observed at the 1st, 2nd, 5th, 10th, 50th, 100th, 200th, and 500th cycles, respectively, and stabilized at a value of around 22 mV after 500 cycles. The Li-ion transport through the mesoporous structure was also observed. + The overpotential, contributed by a robust SEI layer formed on top of the mesoporous structure that allows efficient ion transport, becomes stable after just two cycles.

[0056] In yet another embodiment, the 3D HBCN of the present invention when subjected to sodium metal anode application exhibits a solubility of 8 mAcm as shown in FIG. -2 Current, and 1 and 2 mAhcm -2 The capacitance value shows stable performance even after 1000 cycles, and the coulomb efficiency is approximately 100%.

[0057] The stable electrochemical performance confirms that HBCN enables uniform Li deposition and a stable interface. The conductive carbon matrix with a larger surface area and mesoporous structure leads to low current density distribution and enhanced Li deposition. + Ion transport and uniform electron and Li + Ion distribution is suggested. Moreover, boron and nitrogen dopants act as active sites for homogeneous Li nucleation and guaranteed dendrite-free Li deposition. The expansion of the pore volume adds to the problem of infinite volume expansion by providing space leading to persistent interfaces.

[0058] The as-prepared HBCN anode exhibited a current of 8 mA cm for over 2400 cycles. -2 High current and 10mAhcm -2 When subjected to a heavy Li uptake deposition capacity of 1000mJ / s, it exhibits excellent electrochemical performance and high stability in Li batteries, with a Coulombic efficiency of 99.98%. Full-cell assemblies of prelithiated HBCN with LFP cathodes show stable performance for over 50 cycles. This rationally designed carbon matrix provides an effective strategy for the assembly of stable lithium metal anodes (LMA) and sodium metal anodes (NMA).

[0059] In one embodiment, the present invention provides a -2 High current and 10mAhcm -2We provide 3D HBCNs that exhibit stable dendrite-free Li plating / peeling performance for over 2400 cycles with large volumetric Li uptake. Furthermore, the present invention discloses a facile and cost-effective template-assisted synthesis of 3D HBCNs.

[0060] When a cell is assembled with the anode or cathode against lithium metal, it is called a "half cell." When a cell is assembled with the anode and cathode against each other, it is called a "full cell." [Example]

[0061] The following examples are given by way of illustration and therefore should not be construed as limiting the scope of the invention.

[0062] material: Glucose, cyanamide, tetraethyl orthosilicate (TEOS), boric acid, isopropyl alcohol (IPA), and ammonia solution were procured for the synthesis of HBCN. Conductive carbon (carbon black - 99.99%), polyvinylidene fluoride (PVDF), and N-methyl-2-pyrrolidone were used to prepare the electrodes. Lithium bis(trifluoromethane)sulfonimide lithium salt (LITFSI), dioxolane (DOL), dimethoxyethane (DME), lithium nitrate (LiNO3), lithium hexafluorophosphate (LiPF6), ethylene carbonate (EC), dimethyl carbonate (DMC), fluoroethylene carbonate (FEC), NaPF6, and diglyme were used to prepare the electrolyte. Lithium disks, sodium metal, and Celgard separators were used to assemble the batteries. All materials were used as received.

[0063] Silica NPs were synthesized by the well-known Stöber method using NPs with sizes ranging from 300 to 500 nm and used as templates for HBCN synthesis. Silica NPs generally in the size range of 50 to 500 nm can also be synthesized using the Stöber method. Moreover, commercially available silica NPs in the required size range can also be procured for further HBCN synthesis.

[0064] Example 1: Synthesis of 3D honeycomb boron carbonitride (HBCN) A template-assisted synthesis protocol was used to synthesize HBCN, in which SiO2NPs were used as the template. Typically, 1 molar solutions of boric acid, glucose, and cyanamide were infiltrated with colloidal SiO2NPs. After infiltration, the resulting material was dried at 60 °C and then pyrolyzed at 900 °C for 3 h under argon gas. Next, to completely dissolve and remove the SiO2NPs from the product, the silica / BCN was treated with a 10% HF solution for 12 h, washed with DI water, and dried to obtain 3D HBCN.

[0065] Example 2: Material Characterization The phase purity of the prepared samples was tested from powder XRD analysis performed using a Philips X'Pert PRO analytical diffractometer with nickel-filtered Cu Kα radiation at 1.5406 Å wavelength with 2θ values ​​between 10° and 80°. Raman analysis was performed using a JY Horiba LabRam HR800 micro-Raman spectrometer with a 632.8 nm diode laser. Morphological examination of the prepared samples and the cycled electrodes was carried out using a NOVA NANO FESEM450 instrument at 18 kV working potential and WD = 5.2-5.7 mm. Transmission electron microscopy (TEM) was carried out using an IFEI Tecnai F30 FEG microscope operated with an accelerating potential of 300 kV. Photoelectron spectroscopy (XPS) measurements were carried out using a VG Micro Tech ESCA 3000 instrument with monochromated Al Kα (1486.6 eV) as the x-ray source, and the pressure in the analyzer chamber was kept at 1 × 10 during the measurements. -8 hPa (1×10-8 Surface area tests were performed using the Brunauer-Emmett-Teller (BET) adsorption method with N adsorption up to 1 bar on the surface of the samples, with the aid of a Quantachrome BET surface analyzer.

[0066] Example 3: Electrochemical measurements Electrode preparation: prelithiated anode electrode Electrodes were prepared by mixing 3D HBCN, a conductive additive (Super P), and a PVDF binder in an 80:10:10 ratio using NMP solvent. The prepared slurry was coated onto copper foil, which served as a current collector, and then dried overnight in an oven at 80°C. Circular electrodes were cut to a diameter of 14 mm using an electrode cutter.

[0067] Assembly of the alkali metal cell: The cells were assembled in an Ar-filled glovebox (oxygen level <0.1 ppm and H2O level <0.1 ppm) using a CR2032 cell-type assembly containing Li as the counter and reference electrodes and prelithiated 3D HBCN coated on a copper substrate as the current collector, i.e., anode. The electrolyte used for the Li half-cell was 1 M LiTFSI lithium salt (lithium bis(trifluoromethanesulfonyl)imide) dissolved in a 1:1 (volume) mixture of dioxolane and dimethoxyethane with 0.3 M LiNO3 as an additive. For the full-cell LFP, 1 M LiPF6 in 1:1:1 (v / v / v) EC / DMC / EMC with 5% FEC was used as the electrolyte. Used For Na plating applications, 1 M NaPF6 in diglyme was used as the electrolyte. Celgard was used as the separator to separate the negative and positive electrodes.

[0068] Plating / stripping measurement: The plating-stripping measurements of the prepared materials were carried out at constant charge and discharge using a battery analyzer from MTI Corporation.

[0069] Example 4: Battery Performance Data The cells were performed for HBCN Li plating / stripping at different current and capacity values. To examine the morphological effect along with the heteroatom doping effect, we performed Li plating / stripping on (i) planar carbon sheet (C), (ii) honeycomb carbon (HC), and (iii) boron carbonitride sheet (BCN). Below is a detailed description of the different samples.

[0070] (i) Planar carbon sheet (C): Planar carbon sheets (C) were synthesized by glucose carbonization at 900 °C for 3 h in an argon atmosphere. The as-prepared carbon samples were characterized by XRD and Raman to analyze the phase purity, as shown in Figures 1(a) and 1(b), respectively. Two broad peaks representing the major crystallographic planes (002) and (001) are shown in the XRD. Two strong peaks at 1334 cm correspond to the D and G bands of graphite, respectively, as shown in Figure 1(b). -1 and 1592 cm -1 From BET The calculated surface area of ​​the prepared carbon sheet is 10.7 m 2 g -1 The N2 isotherm is shown in Figure 5(a). The SEM image shown in Figure 2(a) shows the sheet-like morphology of the prepared sample. The 4 mA cm2 showed very poor performance. -2 Current and 10mAhcm -2 The Li plating / stripping performance of the C sample in terms of capacity is shown in the voltage vs. time plot and the Coulombic efficiency vs. cycle plot in Figures 9(a) and (b), respectively. This is due to the material's very small surface area, which provides fewer Li nucleation sites; the planar surface causes inhomogeneous Li deposition, which further develops into dendritic growth. Furthermore, the absence of heterodoping in C leads to poor Li fixation, resulting in poor performance. Within 20 plating / stripping cycles, the Coulombic efficiency drops sharply.

[0071] (ii) Honeycomb carbon (HC): The HC material was synthesized by infiltration of glucose into silica nanoparticles. After infiltration, the resulting material was dried at 60 °C and then pyrolyzed at 900 °C for 3 h in argon gas. Next, to completely dissolve and remove the SiO2 NPs from the product, the silica NPs / carbon composite was treated with a 10% HF solution for 12 h, followed by rinsing with DI water and drying to obtain 3D HC. The phase purity of the sample was characterized by XRD and Raman spectra, as shown in Figures 1(a) and 1(b), respectively, which indicate the complete removal of silica (SiO2) particles from the material after HF treatment. The 3D porous morphology of the honeycomb carbon (HC) is shown in Figure 2(b), with a surface area of ​​276.4 m. 2 g -1 Similar to the flat carbon sheet, the HC sample also exhibited a 4 mAcm -2 Current and 10mAhcm -2 The capacity shows poor Li plating / stripping performance (Figures 9c and d). The Coulombic efficiency dropped within only 40 cycles. The higher surface area of ​​HC compared to the planar carbon sheet provides more Li nucleation sites. However, the lithiphobic nature of carbon and the lack of lithophilic functional groups with strong binding affinity to lithium atoms result in poor performance. This, in turn, leads to non-uniform Li flux distribution and dendrite growth.

[0072] (iii) Boron carbonitride sheet (BCN): BCN was synthesized by incorporating equal molar ratios (1:1:1) of boric acid, glucose, and cyanamide, respectively, and dissolved in distilled water to form a homogeneous solution. This solution was then heated at 70°C until it was converted into a thick paste and allowed to dry completely. The dried material was used as a mortar. pestle The powder was ground at 400°C, transferred to a ceramic boat, and heated in a tube furnace in an argon atmosphere at 900°C for 3 hours. Characterization of the basic material, such as XRD, Raman, SEM, and XPS, confirming the phase purity and elemental analysis for BCN, is shown in Figures 1(a), 1(b), 2(c), and 3, respectively. -2 Current density and 10mAhcm -2The Li plating / peeling performance of the BCN material at the capacitance value is shown in Figure 9(e) and (f), respectively. Similar to the planar carbon and honeycomb carbon materials, poor Li plating / peeling performance was observed for the BCN material. In the case of BCN, although lithophilic dopants B and N are present, the sheet-like morphology provides inhomogeneous Li flux distribution in the material, resulting in poor performance.

[0073] The battery performance of the planar carbon sheet, honeycomb carbon, BCN sheet, and honeycomb BCN indicates that both the honeycomb structure and BN doping into carbon are optimal requirements for uniform Li plating / peeling application.

[0074] Example 5: Comparative Performance Data of Other Forms of Carbon and BCN Table 2 shows the Li plating / stripping performance of different heteroatom-doped carbon materials and the HBCN material of the present invention.

[0075] [Table 2]

[0076] References used in Table 2: 1.Ye W, Pei F, Lan X, Cheng Y, Fang X, Zhang Q, Zheng N, Peng DL, Wang MS. Stable NanoEncapsulation of Lithium Through Seed Free Selective Deposition for High Performance Li Battery Anodes. Advanced Energy Materials. 2020 Feb;10(7):1902956。2.Chen L, Chen H, Wang Z, Gong X, Chen X, Wang M, Jiao S. Self-supporting lithiophilic N-doped carbon rod array for dendrite-free lithium metal anode. Chemical Engineering Journal. 2019 May 1;363:270-7。 3.Huang G, Han J, Zhang F, Wang Z, Kashani H, Watanabe K, Chen M. Lithiophilic 3D nanoporous nitrogen doped graphene for dendrite free and ultra high rate lithium metal anodes. Advanced Materials. 2019 Jan;31(2):1805334。 4.Liu L, Yin YX, Li JY, Wang SH, Guo YG, Wan LJ. Uniform lithium nucleation / growth induced by lightweight nitrogen doped graphitic carbon foams for high performance lithium metal anodes. Advanced Materials. 2018 Mar;30(10):1706216。

[0077] [Table 3]

[0078] References for Table 3: 1.Ultrathin Two-Dimensional Atomic Crystals as Stable Interfacial Layer for Improvement of Lithium Metal Anode. By Kai Yan et.al. Nano letters, 2014; dx.doi.org / Published in Nano Lett. 10.1021 / nl503125u | 2.Composite lithium metal anode by melt infusion of lithium into a 3D conducting Scaffold with lithiophilic coating. Zheng Liang et al. Published in PNAS / 2862-2867 | March 15, 2016 | vol. 113 | no. 11. 3. Engineering stable interfaces for three-dimensional lithium metal by JinXie et.al. Adv. 2018; 4 : eaat5168 27 July 2018.

[0079] While the present invention has been described in detail above for purposes of illustration, it is to be understood that such detail is for purposes only and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention except as may be limited by the claims.

Claims

1. 1. A 3D rigid mesoporous honeycomb boron carbonitride (HBCN) nanomaterial with porosity in the range of 300-500 nm and mesoporosity in the range of 2-10 nm as a host for plating or depositing metals, the metal is selected from lithium, sodium, magnesium, or aluminum; A 3D rigid mesoporous honeycomb boron carbonitride (HBCN) nanomaterial, in which the honeycomb carbon in the nanomaterial is doped with nitrogen and boron.

2. The nanomaterial has a thickness of 400 to 800 m ２ g －１ 2. The 3D rigid mesoporous honeycomb boron carbonitride (HBCN) nanomaterial of claim 1, having a surface area in the range of

3. 10. The 3D rigid mesoporous honeycomb boron carbonitride (HBCN) nanomaterial of claim 1, wherein the nanomaterial plated or deposited with metal as an anode is for alkali metal batteries.

4. a) adding tetraethyl orthosilicate (TEOS) to a mixture of water, alcohol and ammonium solution followed by stirring to provide a reaction mixture, and continuing said stirring to provide silica nanoparticles; b) Separating and washing the silica nanoparticles of step (a) by centrifugation, and then drying to obtain dried colloidal silica nanoparticles (SiO ２ providing NPs; c) A mixture of boric acid, a carbon precursor selected from glucose, sucrose, cellulose, and fructose, and a cyanamide solution is added to form colloidal SiO ２ infiltrating with NPs and drying the resulting material followed by pyrolysis in an inert gas to provide a silica NPs / BCN composite; and d) Treating the silica NPs / BCN of step (c) with HF to remove SiO from the product. ２ completely dissolving the NPs, followed by washing and drying to obtain the 3D rigid mesoporous honeycomb boron carbonitride (HBCN) nanomaterial; 2. The method for producing the 3D rigid mesoporous honeycomb boron carbonitride (HBCN) nanomaterial of claim 1, comprising:

5. 4. An anode for an alkali metal battery comprising the 3D rigid mesoporous honeycomb-shaped boron carbonitride nanomaterial of any one of claims 1 to 3 plated or deposited with lithium or sodium.

6. a) LiFePO as cathode ４ (LFP), b) the 3D rigid mesoporous honeycomb-shaped boron carbonitride nanomaterial according to any one of claims 1 to 3 plated or deposited with lithium as an anode; c) 1 M LiPF in 1:1:1 (v / v / v) ethylene carbonate / dimethyl carbonate / ethyl methyl carbonate with 5% fluoroethylene carbonate as an additive. ６ an electrolyte comprising d) a separator separating the negative and positive electrodes; Lithium-plated full cells, including:

7. The full cell had a capacity of 110 mAhg after 50 cycles. －１ 7. The lithium plated full cell of claim 6 having a capacity of 100% coulombic efficiency.

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